The chronology of cultural, agricultural and demographic change in ancient Sāmoa indicates that population rise is the proximate origin of Polynesian chiefdoms

For decades, the orthodox position has stated that chiefdoms appeared in East Polynesia through demic diffusion as voyagers sailed east from Sāmoa about 1000 years ago, to Hawai’i, Tahiti, and other archipelagos. These voyagers carried with them the germ of sociopolitical hierarchy, originating earlier through innovations in both land tenure and technologies that intensified agricultural production. Demographic variation, such as population rise, is also a contributing factor. The timing of thes innovations and demographic changes in Samoa is, however, poorly understood.

This presentation focuses on recent genetic and demograpic analyses and new archaeological data pertinent to land tenure and agriculture on ‘Upolu Island, Sāmoa. Analyses of modern genetic diversity identify a sharp population rise in Sāmoa 1000 years ago. Archaeological analyses including lidar mapping, pedestrian survey, excavation, and Bayesian chronological modelling reveal land-tenure changes through the construction of large corporate-built rock walls after 900 cal BP and smaller walls, possibly a component of intensified agriculture, built several hundred years later. Chronological, sedimentological, and geochemical analyses of both stream profiles and sediment cores identify human-induced burning of portions of the valley after 670 cal BP, roughly contemporaneous with the construction of ditches and forest removal upslope of ditched areas, additional evidence of intensified agriculture. This all points to population rise as a proximate cause for the evolution of soicopolitical hierarchy in Sāmoa, and perhaps a necessary precondition. We will explore several evolutionary models for the development of sociopolitical hierarchy in light of the Samoan case and question the assumption that cultural diffusion explains sociopolitical hierarchy, chiefdoms, in East Polynesia.

Learn more about Dr. Ethan Cochrane here